Flavoring foodstuffs with a thioester

ABSTRACT

Processes for imparting flavors and aromas to consumable materials, for example vegetable flavors to foodstuffs or perique flavors to tobacco, by adding to such materials a small amount of at least one thioester according to the formula: ##STR1## wherein R 1  is alkyl, aryl, aralkyl, alkaryl, cycloalkyl, or alkenyl and R 2  is alkyl, alkylthioalkyl, aralkyl, alkaryl, or aryl, R 1  containing at least two carbon atoms when R 2  is an alkyl group containing three or four carbon atoms, effective to alter the flavor and/or aroma of such materials, together with compositions containing such thioesters and adapted to alter the flavor and/or aroma of such materials, novel cycloalkyl and alkenyl thiopropionates useful for such purposes, and processes for producing such novel thiopropionates.

This application is a division of application Ser. No. 195,829, filed onNov. 4, 1971, now abandoned.

BACKGROUND OF THE INVENTION

The present invention relates to novel methods and compositionsutilizing certain thioesters, a number of which are novel themselves, toalter the flavor and/or aroma of consumable materials.

There has been considerable work on substances which can be used toimpart flavors to various consumable materials. These substances areused to diminish dependence on natural materials, some of which may bein short supply, and to provide more uniform properties in the finishedproduct. Vegetable flavors, and particularly alliaceous vegetableflavors, are particularly desirable for many uses in consumablearticles.

Furfuryl thioesters have been suggested in United Kingdom Pat. No.1,156,480 for possible use in coffee flavors.Ethyl-α-methyldithiopropionate and ethyl-α-methyldithioisobutyrate havebeen said to possess green or onion-like fragrance notes, andmethanethiol benzoate, methanethiol isovalerate, methanethiolanteisovalerate, methanethiol butyrate, and methanethiol valerate havebeen said to have milky, rotten egg, cheese or gaseous, cabbageodor-flavor contributions in Netherlands Patent Application No.68/12,899.

McFadden, et al., Analytical Chemistry 37,560, have suggested thepresence of methyl thiohexanoate and thioheptanoate in oil derived fromhops, and Buttery, et al., have reported similar work in J.Chromatography 18,399. See also Schultz, Day, and Libbey, The Chemistryand Physiology of Flavors, Westport, Conn.: Avi. 1967, especially atpage 412. S-Alkyl derivatives of thioacetic, thioacrylic, andthiobutyric acids have been prepared and are described asdisagreeable-smelling liquids. Boehme, et al., Annalen, 648, 15describes vinyl thioacetate as ill-smelling.

Showell, et al., J. Org. Chem., 27, 2853-8 (1962) show syntheses ofcyclohexyl and cyclopentyl thioacetates but do not indicate flavorutility or properties.

Schleppnik and Zenty, J. Org. Chem. 29, 1910-15 (1964) demonstratesyntheses of alkyl(3-alkylthio)thiopropionates via 3-alkylthioacylchloride intermediates. Synthesis of methyl(3-methylthio)thiopropionateis set out in U.S. Pat. No. 2,888,480. Thioesters are shown in U.S. Pat.Nos. 2,550,141; 2,259,869; and 3,369,979. U.S. Pat. No. 3,103,464 showsvarious thioesters, including allyl thioacetate, butenyl thioacetate,cyclohexyl thioacetate, and butyl thiobenzoate.

THE INVENTION

It has now been discovered that certain alkyl, aryl, cycloalkyl, andalkenyl S-esters of thio acids can be used to impart good vegetableflavor character to foodstuffs, and they can also be used to providepleasant notes such as perique-like flavor notes in tobacco products.More specifically, small amounts of thioesters having the formula:##STR2## wherein R₁ is alkyl, cycloalkyl, aryl, aralkyl, alkaryl, oralkenyl, R₂ is alkyl, alkyl thioalkyl, aralkyl, alkaryl, or aryl, R₁containing at least two carbon atoms when R₂ is an alkyl group havingthree or four carbon atoms or phenyl, are used according to thisinvention to alter the flavor and/or aroma of consumable materials. Itis further contemplated according to the present invention thatcompositions containing effective amounts of such thioesters also beused for altering flavors and aromas.

Two of the compounds contemplated herein are novel. The novel compoundsare an alkenyl thioester, allyl thiopropionate, and a cycloalkylthioester, cyclopentyl thiopropionate, both of which can be representedby the generic formula: ##STR3## wherein R₃ is cyclopentyl or allyl.

Thioesters useful in the instant invention, including the novelthioesters can be prepared according to the method of Wenzel and Reid,J. Am. Chem. Soc. 59, 1089 (1937) by reaction of an acyl halide and theappropriate mercaptan. Thus, allyl thiopropionate is produced byintimately admixing propionyl chloride and allyl mercaptan at atemperature in the range of -10° to +40° C. at atmospheric pressure.Similarly, cyclopentyl thiopropionate is produced by intimately admixingcyclopentane thiol and propionyl chloride at a temperature in the rangeof -10° to +40° C.

The alkyl 3-(alkylthio)thio acid esters are desirably produced byadmixing acroyl chloride and alkyl mercaptan at a temperature in therange of -10° to +40° C. Thus, acroyl chloride and methyl mercaptan arereacted to provide methyl3-(methylthio)thiopropionate. In the samemanner ethyl (3-ethylthio)thiopropionate is produced from acroylchloride and ethyl mercaptan; propyl(3-propylthio)thiopropionate, fromacroyl chloride and propyl mercaptan, and so on. Methyl3-(ethylthio)thiopropionate and ethyl 3-(methylthio)thiopropionate areproduced in admixture using acroyl chloride and mixtures of methylmercaptan and ethyl mercaptan in various proportions, depending upon theproportions of methyl 3-(ethylthio)thiopropionate to ethyl3-(methylthio)thiopropionate desired in the final reaction product. Ifdesired the various compounds produced in the reaction product can beseparated to provide

a. methyl 3-(ethylthio)thiopropionate

b. ethyl 3-(methylthio)thiopropionate

c. methyl 3-(methylthio)thiopropionate

d. ethyl 3(ethylthio)thiopropionate

The reaction is broadly described in two steps as follows: ##STR4## Itwill be noted than an intermediate alkylthioacyl halide is first formedby reaction of one mole of mercaptan with one mole of acroyl halide. Onaddition of an additional mole of mercaptan the alkylthioacyl halideintermediate is converted into the desired alkyl3-(alkylthio)thiopropionate. R₅ represents a lower alkyl group,preferably one having from one to three carbon atoms. The above alkylacyl halides used herein have the generic formula: ##STR5## wherein itwill be understood that only a single alkyl group is referred to becauseof considering only a single molecule at a time. If mixed mercaptans areused, the alkyl groups resulting in the finished products will also bemixed. R₁ has the meaning as set forth herein above.

The reaction is carried out at atmospheric or superatmosphericpressures. Atmospheric pressures are preferred, except in the case ofhighly volatile reactants or where the temperature of reaction ismaintained greater than 10° C., in which case superatmospheric pressuresare preferred. Except in the case when alkyl3-(alkylthio)thiopropionates are produced, the mole ratio of acyl halideto mercaptan is in the range of about 0.5:1 to about 1:1 with a 1:1 moleratio preferred. If lower mole ratios are used, excess mercaptan must beremoved at the end of the reaction (via distillation or otherappropriate techniques). Where alkyl 3-(alkylthio)thiopropionates areproduced, the mole ratio of acyl halide to mercaptan is in the range ofabout 0.25:1 to about 0.5:1, with the 0.5:1 mole ratio preferred. Highermole ratios can produce an excess of alkylthioacyl halide intermediatewhich is difficult to recycle.

The presence of a reaction vehicle is not necessary but the reaction cantake place in a non-reactive volatile vehicle, preferably a solvent suchas diethyl ether or cyclohexane. The advantage of using such a vehicleis that better control of the reaction is achieved. This is particularlyadvantageous when carrying out the reaction on an industrial scale. Inthe alternative, excess mercaptan can be used as a reaction solvent, butuse of higher molecular weight mercaptans can give rise to difficultiesin purifying the reaction product.

After the reaction is terminated the reaction mass is "worked up" usingthe conventional extraction and distillation procedures, such as thosedescribed by Wenzel and Reid or McFadden, et al., mentioned above.

As used herein, consumable material includes foodstuffs, flavoringcompositions, tobacco and tobacco products, and the like in which thearoma and/or flavor is altered. It will thus be understood thatcompounds according to this invention can be utilized to alter theflavor and/or aroma of a wide variety of materials which are ingested orotherwise consumed.

In the present invention, useful materials are those wherein the alkyl,aryl, aralkyl, cycloalkyl, and alkenyl groups represented by R₁ aredesirably groups containing from 1 to 10 carbon atoms. The alkyl andalkenyl groups can be straight-chain or branched-chain. The aryl groupscontain 6 to 10 carbon atoms and aralkyl groups contain 7 to 10 carbonatoms. The cycloalkyl groups can be mono- or polyalkyl-substituted.Thus, preferred, alkyl, aryl, aralkyl, cycloalkyl and alkenyl groupsaccording to the present invention include methyl, ethyl, n-propyl,isoproypl, n-butyl, i-butyl, amyl, heptyl, phenyl, tolyl, xylyl,phenylmethyl, phenylethyl, phenylpropyl, tolylpropyl, cyclopentyl,cyclohexyl, and allyl. In certain preferred embodiments of thisinvention, R₁ represents methyl, ethyl, propyl, allyl, or cyclopentyl.

The alkyl groups represented by R₂ contain from 1 to 10 carbon atoms andthey desirably contain from 1 to 3 carbon atoms. Thus, preferred alkylgroups include methyl, ethyl and propyl. The alkylthioalkyl groupsrepresented by R₂ contain 2 to 6 carbon atoms and a preferredalkylthioalkyl group is methylthioethyl. The aryl groups encompassed byR₂ include substituted and unsubstituted mono- and polynuclear arylgroups. A particularly preferred aryl is phenyl. The aralkyl groupsencompassed by R₂ include phenylmethyl and phenylethyl. In certainpreferred embodiments, R₂ represents methyl, ethyl, propyl, and phenyl.It will be understood that when R₂ is phenyl or an alkyl groupcontaining three or four carbon atoms, R₁ contains at least two carbonatoms.

The thioesters used according to the present invention are, in manyinstances, commercially available from various suppliers, although asstated above certain materials used herein are novel. Regardless of thesource of the thioester or thioesters, these substances should be freefrom any deleterious impurities which affect their suitability for usein flavors. In many instances, it is desirable to have the thioesters beat least 95 percent pure.

Cyclopentyl thiopropionate has a characteristic taste of fresh onion at0.5 to 2 ppm (parts per million). At 5 ppm, fruity notes are added tothis character with a lingering onion aftertaste, such as is noted whenfresh onions are eaten. This compound is very interesting for use inonion flavors, and has a threshold level of about 0.2 ppm. It can beused at levels on the order of 4 ppm. All parts, percentages,proportions, and ratios herein are by weight, unless otherwise,indicated.

Propyl thioacetate has a sharp, fresh onion odor with a burning aromacharacteristic. When tasted in aqueous solution at 0.1 to 5.0 ppm, ithas a fresh onion flavor with a lingering onion aftertaste.

Allyl thiopropionate has a very characteristic fresh garlic odor inaqueous solution at 0.02 to 0.5 ppm. At 10 ppm aqueous solution has acooked garlic flavor with a light metallic and burning aftertaste.

Methyl thiopropionate has a cooked cabbage-broccoli odor at 0.1 to 5ppm. A 10 ppm aqueous solution has a cooked brussel sprouts/broccoliflavor with a light bitter after-taste. At higher use levels, it has afruit-like flavor.

n-Propyl thiopropionate has an odor of freshly sliced onions in aqueoussolution at 1 ppm. Aqueous solutions containing from 0.01 to 2.2 ppmhave a taste like fresh onion juice with a long-lingering aftertaste. Italso lends a pleasant note to burning tobacco at levels of 5-15 ppm.

Methyl thioacetate in ethanolic solution at 0.01 ppm has a sweet,nut-like creamy taste. At 0.1 ppm it has a popcorn-cereal taste, whileat one ppm a cabbage, vegetable aroma and taste are dominant. Thismaterial is suitable for milk, bread, and popcorn flavors at low levelsand can be used at higher levels for vegetable, especially cabbage,flavors. Its threshold level is about 0.005 ppm.

Ethyl thioacetate has an odor in alcoholic solution at levels of 0.01 toone percent like meat extract. In water at 0.05 ppm, near the thresholdlevel, it has an aroma reminiscent of meat extract and hydrolyzedvegetable protein, and a taste which is slightly sweet andcharacteristic of beef extract. Similarly, at 0.1 ppm it has acharacteristic aroma and taste of beef extract. In chicken soup, itdeepens the taste at 0.01 ppm, and at 0.2 ppm it increases the meatflavor notes and enhances the flavor, much along the lines of monosodiumglutamate. At 0.5 ppm it introduces beef flavor notes with a verypleasant, full meat aftertaste in chicken soup. It also has vegetableflavor notes.

Alkyl thiobenzoate has a very characteristic garlic salami aroma inaqueous solution at 0.02 up to 0.5 ppm. At 10 ppm the aqueous solutionhas a fruity onion aroma with a bitter note.

Propyl thiobenzoate has an onion aroma and a fruit/onion taste at0.02-0.2 ppm. At 10 ppm it has a sweet fruity taste with an onionbacknote.

Methyl 3-(methylthio)thiopropionate has a cabbage/cauliflower-like aromaand taste and in addition a bready yeasty character from 0.2 up to 1ppm. At 10 ppm it has a lingering metallic green note. Its use level isfrom 0.2 up to 1 ppm.

Methyl thiobenzoate has been found to lend a perique tobacco note totobacco at levels of 5-15 ppm.

It will be appreciated from the present disclosure that the thioesterscan be used to alter, vary, fortify, modify, enhance, or otherwiseimprove the flavor or aroma of a wide variety of materials which areingested, consumed, or otherwise organoleptically sensed.

The term "alter" in its various forms will be understood herein to meanthe supplying or imparting a flavor character or note to an otherwisebland, relatively tasteless substance, or augmenting an existing flavorcharacteristic where the natural flavor is deficient in some regard, orsupplementing the existing flavor impression to modify organolepticcharacter.

The thioesters and mixtures thereof are accordingly useful in flavoringcompositions. A flavoring composition is taken to mean one whichcontributes a part of the overall flavor impression by supplementing orfortifying a natural or artificial flavor in a material as well as onewhich supplies substantially all the flavor and/or aroma character to aconsumable article.

The term "foodstuff" as used herein includes both solid and liquidingestible materials for man or animal, which materials usually do, butneed not, have nutritional value. Thus, foodstuffs include meats,gravies, soups, convenience foods, malt, alcoholic, and other beverages,milk and dairy products, seafoods including fish, crustaceans, mollusks,and the like, candies, vegetables, cereals, soft drinks, snacks, dog andcat foods, other veterinary products, and the like. It will beunderstood by those skilled in the art that the thioesters can be usedto impart vegetable, meat, and other flavor notes to foodstuffs asaforementioned whenever such notes are desired.

When the thioesters of this invention are used in a flavoringcomposition, they can be combined with conventional flavoring materialsor adjuvants. Such co-ingredients or flavoring adjuvants are well knownin the art for such use and have been extensively described in theliterature. Apart from the requirements that any such adjuvant materialbe ingestibly acceptable, and thus non-toxic or otherwisenondeleterious, conventional materials can be used and broadly includeother flavor materials, vehicles, stabilizers, thickeners, surfaceactive agents, conditioners and flavor intensifiers.

Such conventional flavoring materials include saturated, unsaturated,fatty and amino acids; alcohols, including primary and secondaryalcohols; esters, carbonyl compounds including ketones and aldehydes;lactones; other cyclic organic materials including benzene derivatives,alicyclics, heterocyclics such as furans, pyridines, pyrazines and thelike or derivatives thereof; other sulfur-containing materials includingthiols, sulfides, disulfides and the like; proteins; hydrolyzedvegetable protein; lipids; carbohydrates; so-called flavor potentiatorssuch as monosodium glutamate, guanylates, and inosinates; naturalflavoring materials including natural onion oils and natural garlicoils; essential oils and extracts; artificial flavoring materials; andthe like.

More particularly, vegetable-type flavoring compositions desirablycontain, in addition to a thioester or thioesters, at least one ofdipropyl disulfide, diallyl disulfide, propyl propenyl disulfide,2-methoxy-3-isobutyl pyrazine and 2-isobutyl thiazole. Furthermore, thethioesters of this invention are useful in completing natural as well assynthetic onion and/or garlic oil formulations. Examples of suchsynthetic onion and garlic oil compositions which can be enhanced arethose utilizing alkyl 1-alkenyl sulfides, as shown for instance in U.S.Pat. No. 3,615,601.

Stabilizers include preservatives such as sodium chloride, and the like,antioxidants such as calcium and sodium ascorbate, ascorbic acid,butylated hydroxyanisole, butylated hydroxytoluene, propyl gallate, andthe like; sequestrants such as citric acid, ethylenediamine tetraceticacid, phosphates, and the like.

Thickeners include materials such as carriers, binders, protectivecolloids, suspending agents, emulsifiers and the like, such asagar-agar, carrageenan, cellulose and cellulose derivatives such ascarboxymethyl cellulose and methyl cellulose, natural and synthetic gumssuch as gum arabic, gum tragacanth and the like, and other proteinaceousmaterials, lipids, carbohydrates, starches, and pectins.

Surface active agents includle emulsifying agents such as mono- and/ordiglycerides of fatty acids such as capric acid, caprylic acid, palmiticacid, stearic acid, oleic acid, myristic acid, and the like; lecithin;defoaming and flavor-dispersing agents such as sorbitan monostearate,potassium stearate, hydrogenated tallow alcohol, and the like.

Conditioners include compounds such as bleaching and maturing agentssuch as benzoyl peroxide, calcium peroxide, hydrogen peroxide and thelike; starch modifiers such as peracetic acid, sodium chlorite, sodiumhypochlorite, propylene oxide, succinic anhydride and the like, buffersand neutralizing agents such as sodium acetate, ammonium bicarbonate,ammonium phosphate, citric acid, lactic acid, vinegar and the like;colorants such as carminic acid cochineal, turmeric, curcumin, and thelike; firming agents such as aluminum sodium sulfate, calcium chlorideand calcium gulconate; texturizers; anti-caking agents such as aluminumcalcium sulfate and tribasic calcium phosphate; enzymes; yeast foodssuch as calcium lactate and calcium sulfate; nutrient supplements suchas iron salts such as ferric phosphate, ferric pyrophosphate, ferrousgluconate and the like, riboflavin, vitamins, zinc sources such as zincchloride, zinc sulfate, and the like.

The thioesters or mixtures thereof or the compositions incorporatingthem, as mentioned above, can be combined with one or more vehicles orcarriers for adding them to the particular product. Vehicles can beedible or otherwise suitable materials such as ethyl alcohol, propyleneglycol, water, and the like. Carriers include materials such as gumarabic, carrageenen, other gums, and the like. The thioester can beincorporated with the carriers by conventional means such asspray-drying, drum-drying, and the like. Such carriers can also includematerials for coacervating the thioesters of the present invention (andother flavoring ingredients, as present) to provide encapsulatedproducts. When the carrier is an emulsion, the flavoring composition canalso contain emulsifiers such as mono- and diglycerides of fatty acidsand the like. With these carriers or vehicles the desired physical formof the composition can be prepared.

It will be understood by those skilled in the art that the thioester orthioesters can be added to the materials to be flavored at anyconvenient point in the production of the finished product. Thus, whenthe thioester is used to alter or otherwise vary the flavor of afoodstuff, it can be added in the original mixture, dough, emulsion,batter, natural product, or the like prior to any cooking or heatingoperation. Alternatively, it can be added at a later stage of processingif volatilization losses would be excessive during the earlierprocessing. The quantity of thioester utilized should be sufficient toimpart the desired vegetable flavor characteristic to the product, buton the other hand, the use of an excessive amount of such thioesters isnot only wasteful and uneconomic, but too large a quantity unbalancesthe flavor of the product consumed. Moreover, at too high a level inflavoring compositions (and also in foodstuffs) the vegetable or otherpleasant food character of the thioesters will be lost.

The quantity used will vary depending upon the ultimate foodstuff, orother consumable product; the amount and type of flavor initiallypresent in the product; the further process or treatment steps to whichthe product will be subjected; regional and other preference factors;the type of storage, if any, to which the product will be subjected; andthe pre-consumption treatment, such as baking, frying, and so on, givento the product by the ultimate consumer. Accordingly, the terminology"effective amount" and "sufficient amount" is understood in the contextof the present invention to be quantitatively adequate to alter theflavor of the foodstuff, tobacco, or other consumable material.

Thioesters according to this invention can also be used to improve andaugment the organoleptic properties of tobacco and tobacco products.Thus, for example, methyl thiobenzoate conveys a perique-type of note totobacco. Tobacco, as used herein, includes natural tobaccos such asburley, Turkish tobacco, Maryland tobacco; tobacco-like products such asreconstituted tobacco or homogenized tobacco; and tobacco substitutesintended to replace natural tobacco such as various vegetable leaves,for example lettuce and cabbage leaves and the like.

When the thioesters are used to treat tobacco products, the additive canbe applied in a suitable manner, as by spraying, dipping or otherwise.The thioesters or compositions containing them can be applied during the"casing" or final spray treatment of the tobacco, or they can be appliedat some earlier stage of curing or preparation. The quantity ofthioesters or mixtures thereof utilized should be sufficient to impartthe desired flavor characteristic to the product; on the other hand, theuse of an excessive amount of the thioesters is not only wasteful anduneconomic, as noted above, but in some instances too large a quantitymay unbalance the flavor or other organoleptic property of the productconsumed.

It is accordingly highly desirable that the ultimate compositionscontain from about 0.005 to about 40 ppm of the thioester or thioesters.More particularly, in food compositions it is preferred to use fromabout 0.01 to about 10 ppm.

The amount of thioesters to be utilized in flavoring compositions can bevaried over a wide range depending upon the particular quality to beadded to the foodstuff or other consumable material. Thus, amounts ofthe thioester according to the present invention from about 0.1 percentup to 80 or 90 percent can be incorporated in such compositions. It isgenerally found to be desirable to include from about 0.5 to about 50percent of thioester in such compositions.

The following examples are given to illustrate embodiments of theinvention as it is presently preferred to practice it. It will beunderstood that these examples are illustrative, and the invention isnot to be considered as restricted thereto except as indicated in theappended claims.

EXAMPLE I Preparation of Allyl Thiopropionate

Propionyl chloride (45 g, 0.5 mole) is placed in a 250 ml flask equippedwith a stirrer, addition funnel and thermometer, and is cooled to 5° C.Then, 37 g (0.5 mole) of allyl mercaptan is added dropwise over a30-minute period while constantly stirring the reaction mixture andmaintaining the temperature at 5° C. The reaction mixture is allowed towarm to room temperature and allowed to remain at room temperature for 2days.

The reaction mixture is added to 500 ml distilled water and the mixtureis transferred to a separatory funnel. The aqueous layer is separatedand discarded and the organic layer, after drying over calcium chloride,is distilled under reduced pressure.

The product is obtained as a colorless liquid with b.p. 77° C. at 10 mmHg. Yield 21.8 g of greater than 95 percent purity as shown by coupledgas chromatography/mass spectrometric analysis.

The allyl thiopropionate has the following mass fragmentation pattern,in order of decreasing ion abundance, m/e: 57, 29, 27, 39, 41. Theinformation yielded by these data are consistent with the structure##STR6##

EXAMPLE II Preparation of Cyclopentyl Thiopropionate

Propionyl chloride (18.4 g, 0.2 mole) is placed in a 250 ml flaskequipped with stirrer, additional funnel and thermometer, and is cooledto 5° C. Then, 20.4 g (0.2 mole) cyclopentanethiol is added dropwiseover a 30-minute period while constantly stirring the reaction mixtureand maintaining the temperature at 5° C. The reaction mixture is allowedto warm to room temperature and is allowed to stand at room temperaturefor 3 days.

The reaction mixture is added to 150 ml water and the organic layer iscollected. After drying over calcium chloride the product is distilledunder reduced pressure to yield pure cylcopentyl thiopropionate (15.7 g)with b.p. 95° C. at 20 mm Hg.

The product shows the following mass fragmentation pattern, in order ofdecreasing abundance, m/e: 57, 29, 41, 158, 27, 91.

The foregoing data are consistent with the structure ##STR7##

EXAMPLE III

The following mixture is prepared:

    ______________________________________                                        Ingredient           Parts                                                    ______________________________________                                        Allyl thiopropionate 30                                                       Natural garlic oil   70                                                       ______________________________________                                    

The mixture is compared with the pure natural garlic oil at the level of0.5 ppm in water. The above mixture has a substantially fresher andfuller garlic taste than does the natural garlic oil alone. The flavorstrengths of the two solutions are considered to be closely similar.

The foregoing test gives rise to the conclusion that allylthiopropionate is very useful in reconstituting imitation garlic oilsand adding fresher garlic notes to other garlic products.

EXAMPLE IV

The following mixture is prepared:

    ______________________________________                                        Ingredient           Parts                                                    ______________________________________                                        Propyl thiopropionate                                                                              20                                                       Natural onion oil    80                                                       ______________________________________                                    

The mixture is compared with the pure onion oil at the rate of 0.5 ppmin water. The mixture has fuller and fresher aroma and tastecharacteristics than the natural onion oil alone. The flavor strength ofthe mixture as compared to the pure natural onion oil is the same.

The foregoing gives rise to the conclusion that propyl thiopropionate isuseful in reconstituting imitation onion oils with onion aroma and tastecharacteristics.

EXAMPLE V

    ______________________________________                                        Ingredient           Parts                                                    ______________________________________                                        Propyl thioacetate   20                                                       Propyl thiopropionate                                                                              30                                                       Cyclopentyl thiopropionate                                                                         50                                                       ______________________________________                                    

The above ingredients are thoroughly homogenized at 25° C. The mixturehas an excellent onion flavor.

EXAMPLE VI

Three meat loaf type products are prepared according to the followingformulation:

    ______________________________________                                        Ingredient                Amount                                              ______________________________________                                        TVP, minced*              1 cup                                               Ground beef               1 cup                                               Water                     1 cup                                               Beef suet                 1/3 cup                                             Bread crumbs, dry, unflavored                                                                           1 cup                                               Whole milk                1 cup                                               Egg albumen               3 tbsp.                                             Salt                      11/4 tbsp.                                          Black pepper              1/4 teasp.                                          Catsup                    1/4 cup                                             Water                     32 ml.                                              ______________________________________                                         "TVP" is a texturized vegetable protein mixture made by                       ArcherDaniels-Midland Company.                                           

Three separate portions prepared according to the foregoing formulationare made into three meat loaves. Loaf A contains no additional additive.Loaf B contains 32 ml. of fresh pressed onion juice to replace the 32ml. of water, and Loaf C contains 5 ppm of the mixture prepared inExample V. The three loaves are baked at 350° F. for 1 hour.

The Loaves B and C are judged superior to Loaf A because the onioncharacter of B and C enhances the overall taste and covers the dry,cardboard-like cereal character of Loaf A.

EXAMPLE VII Tobacco Flavor Containing Methyl Thiobenzoate

The following mixture is prepared:

    ______________________________________                                        Ingredient           Parts                                                    ______________________________________                                        Methyl thiobenzoate  10                                                       Tobacco absolute*    450                                                      Caproic acid         20                                                       Geraniol             20                                                       Absolute ethanol     500                                                      ______________________________________                                         *Tobacco absolute is a commercially available product prepared by Adrien      Co., 15 Rue de Cassis, Marseilles, France.                               

The foregoing solution is applied to an aged, cured, and shreddeddomestic Burley tobacco in an amount to provide tobacco compositionscontaining 1/4, 1/2, and 3/4 percent, respectively, of the mixture on adry basis. Thereafter, the alcohol barrier is removed by evaporation,and the tobacco is manufactured into cigarettes by conventional means.

The tobaccos treated as indicated have a desired and pleasing "perique"aroma which is detectable in the main and side smoke streams when thecigarette is smoked.

EXAMPLE VIII Use of Ethyl Thioacetate for Synthetic Meat Flavor

The following mixture (A) is prepared:

    ______________________________________                                        Ingredient           Parts                                                    ______________________________________                                        L-cysteine hydrochloride                                                                           1.71                                                     Carbohydrate-free vegetable                                                   protein hydrolysate  28.63                                                    Thiamine hydrochloride                                                                             1.71                                                     Water                67.95                                                    ______________________________________                                    

This mixture is refluxed for 4 hours and aged for 3 days to producereaction product "B".

The following mixture is then produced:

    ______________________________________                                        Ingredient           Parts                                                    ______________________________________                                        Sodium chloride      30                                                       Monosodium glutamate 20                                                       Maltodextrin         30                                                       Levulinic acid        1                                                       Reaction product "B" 18                                                       Ethyl thioacetate     1                                                       ______________________________________                                    

The resulting product has an intense roasted meat flavor, the "roasted"note being augmented by means of the addition of the ethyl thioacetate.

EXAMPLE IX

A beef gravy is made by formulating a gravy flavor composition of thefollowing ingredients in the amounts indicated.

    ______________________________________                                        Ingredient           Gms./unit                                                ______________________________________                                        Cornstarch           10.50                                                    The product of Example VIII                                                                        3.00                                                     Carmel color         .30                                                      Garlic powder        .05                                                      White pepper         .05                                                      Salt                 1.92                                                     Monosodium glutamate .20                                                      ______________________________________                                    

To one unit of gravy flavor concentrate, 8 ounces of water are added,and the mixture is stirred thoroughly to disperse the ingredients,brought to a boil, simmered for 1 minute, and served. This "meatless"gravy exhibits excellent beef flavor.

EXAMPLE X Tobacco Flavor Mixture Containing Propyl Thiopropionate

The following mixture is prepared:

    ______________________________________                                        Ingredient           Parts                                                    ______________________________________                                        Propyl thiopropionate                                                                              10                                                       Tobacco absolute*    450                                                      Caproic acid         20                                                       Genaniol             20                                                       Absolute ethyl alcohol                                                                             500                                                      ______________________________________                                         *Tobacco absolute as in Example VII.                                     

The foregoing solution is spread onto shredded and blended domestictobacco to produce a 0.005 percent level of propyl thiopropionate on thetobacco. After the ethyl alcohol is evaporated from the treated tobacco,cigarettes are made having a standard cellulose acetate filter.

A second quantity of shredded and blended domestic tobacco is spreadwith the same relative quantity of ethyl alcohol and with all theingredients of the above mixture, but the propyl thiopropionate isomitted. After the ethyl alcohol is evaporated from the tobacco,cigarettes are made having a standard cellulose acetate filter. Thissecond group of cigarettes is used as the control for testing purposes.

Both the propyl thiopropionate-treated cigarettes and the controlcigarettes are smoked by experts. The result of the expert testsdemonstrates a preference for the propyl thiopropionate over the controlcigarettes.

EXAMPLE XI

A 0.9 cc portion of a 0.1 percent solution of allyl thiobenzoate inpropylene glycol is added to 7.3 gms of a soup basis consisting of

    ______________________________________                                        Ingredient           Quantity                                                 ______________________________________                                        Fine ground sodium chloride                                                                        35.62                                                    Hydrolyzed vegetable protein                                                                       27.40                                                    Monosodium glutamate 17.81                                                    Sucrose              10.96                                                    Beef fat             5.48                                                     Sethness caramel color                                                                             2.73                                                     ______________________________________                                    

The resulting mixture is added to 12 ozs. of boiling water to create asoup having an excellent garlic-salami flavor.

EXAMPLE XII

The following ingredients are refluxed for four hours, aged for threedays, and spray-dried to produce a solid product having a beef flavor.Before drying, sufficient gum arabic is added to provide a compositioncontaining 0.5 part gum arabic and one part flavor solids.

    ______________________________________                                        Ingredient           Parts                                                    ______________________________________                                        L-Cystein hydrochloride                                                                            1.32                                                     Carbohydrate-free vegetable                                                    protein hydorlysate 22.05                                                    Ethyl thioacetate    22.00                                                    Thiamine hydrochloride                                                                             1.32                                                     beta-Alanine         .50                                                      Water                53.31                                                    ______________________________________                                    

A similar reaction product without the ethyl thioacetate in thereactants does not have as characteristic a meaty note as does theproduct with the ethyl thioacetate.

Food flavors are similarly enhanced and improved utilizing methylthiopropionate, methyl thioacetate, propyl thiobenzoate, methyl3-(methylthio)propionate, and like substances and combinations thereofaccording to the present invention.

It will be appreciated from the foregoing description that methylthiobenzoate is particularly suited to the production of tobacco (whichterm is also taken herein to include tobacco products such as cigarettesand cigarette tobacco, cigars and cigar tobacco, pipe tobacco, snuff,chewing tobacco, and the like) to provide interesting and novel flavorsof the perique type. Such use of methyl thiobenzoate and compositionssuitable for carrying out such use are also contemplated within thepresent disclosure.

What is claimed is: .[.1. A process for altering the flavor of a foodstuff which comprises adding thereto a small flavor-altering amount of at least one thioester having the formula: ##STR8## wherein R is alkyl, aryl, aralkyl, alkaryl, cycloalkyl or alkenyl and R₂ is alkylthioalkyl, aralkyl, alkaryl or aryl, R₁ containing at least two carbon atoms when R₂ is phenyl or an alkyl group containing three to four carbon atoms..]. .[.2. A process according to claim 1 wherein R₁ contains from one to ten carbon atoms..]. .[.3. A process according to claim 1 wherein R₂ is alkyl containing from one to ten carbon atoms or an alkylthioalkyl group containing from 2 to 6 carbon atoms or phenyl or phenylmethyl or phenylethyl aralkyl group..]. .[.4. A process according to claim 1 wherein the consumable material contains from about 0.005 to about 40 ppm of thioester..]. .[.5. A process as claimed in claim 1 wherein said thioester is ethyl thioacetate..]. .[.6. A process as defined in claim 1 wherein said thioester is allyl thiopropionate..]. .[.7. A process as defined in claim 1 wherein said thioester is propyl thioacetate..]. .[.8. A food flavor-altering composition which contains as an essential ingredient from about 0.1 to 90 percent by weight of the total composition of at least one thioester according to the formula: ##STR9## wherein R₁ is alkyl, aryl, aralkyl, alkaryl, cycloalkyl or alkenyl and R₂ is alkyl, alkylthioalkyl, aralkyl or alkaryl, R₁ containing at least two carbon atoms when R₂ is phenyl or an alkyl group containing three to four carbon atoms, and another flavoring agent selected from the group consisting of 2-methoxy-3-isobutyl pyrazine, 2-isobutylthiazole, dipropyl disulfide, dialkyl disulfide, propyl propenyl disulfide and mixtures thereof..]. .Iadd.
 9. A process for augmenting or enhancing the flavor of a foodstuff which comprises adding thereto from about 0.005 ppm up to about 40 ppm of a thioester selected from the group consisting of allylthiobenzoate, propylthiobenzoate, methyl-3-(methylthio) thiopropionate, propylthiopropionate, allylthiopropionate, and cyclopentylthiopropionate. .Iaddend. .Iadd.
 10. The process of claim 9 wherein the thioester is allylthiobenzoate. .Iaddend..Iadd.
 11. The process of claim 9 wherein the thioester is propylthiobenzoate. .Iaddend..Iadd.
 12. The process of claim 9 wherein the thioester is methyl-3-(methylthio) thiopropionate. .Iaddend..Iadd.
 13. The process of claim 9 wherein the thioester is propylthiopropionate. .Iaddend..Iadd.
 14. The process of claim 9 wherein the thioester allylthiopropionate. .Iaddend..Iadd.
 15. The process of claim 9 wherein the thioester is cyclopentylthiopropionate. .Iaddend. 